A new, seismically sound San Francisco General Hospital would cost about $622 million, although city voters must first approve a bond measure to foot the bill.

Instead of tearing down existing buildings on the Potrero Hill campus, the public hospital could build at least 385,747 square feet on its west lawn, according to a feasibility study released Monday. Architectural plans call for an expansive basement in an effort to minimize the height of the new building and make room for diagnostic and interventional uses.

California hospitals must comply with a state law requiring acute care facilities to be rebuilt, retrofitted or closed by 2008. All hospital buildings must be capable of sustaining a major earthquake by 2030, the law says. Gov. Schwarzenegger is considering another bill that would extend the 2008 deadline to 2015 for some hospitals that have requested an extension and already have their projects under way.

The Board of Supervisors Government Audit and Oversight Committee on Monday considered plans for the 230 new beds — each with $2.7 million in associated costs — at San Francisco General. The total cost of $780 million includes about $158 million for furniture, fixtures and equipment.

“We seem to be on the right track,” said Supervisor Sophie Maxwell, who represents the hospital area along with Supervisor Tom Ammiano. “It’s intriguing.”

Ammiano described the proposed design as creative — one that employs maximum function with minimum form.

“The first presentation seems very, very positive,” Ammiano said.

The plan put together by architectural firm Anshen and Allen calls for 120 psychiatric and skilled nursing beds to remain in the existing building and ambulances taking a different route in an effort to disturb neighbors less.

Mayor Gavin Newsom decided in February to delay asking voters to pass a bond to pay for the new hospital building until 2008. Newsom has said the upgrade is one of his top priorities but because costs were not known earlier this year, the mayor decided to hold off on the bond. A two-thirds vote is needed to pass the measure.